[The spleen--still a puzzling organ?]

The model of animal experiments developed in the sixties by the Erfurt investigation team of A. Sundermann, according to which autoimmunisation phenomena may be evoked in the rabbit by the application of warmth-alterated autologous blood cells, undergoes a repeated critical consideration on the basis of the modern knowledge of the nature of the autoimmunisation process. In this case must be stated that the importance of the spleen for the development of such processes is finally still unclear. The favourable therapeutical effects of a splenectomy observed in the model and also in clinical routine work cannot be explained sufficiently theoretically, particularly on the basis of the recent results of research concerning the cellular immune mechanisms. No doubt, it seems to be clear that the spleen is authoritatively responsible for the primary immune response, however it remains questionable, whether an isolated primary response is really existing, since on its part it already depends on T-lymphocytes which stimulate the secondary response. However, a splenectomy might be suitable theoretically--if at all--for the interruption of the immune process only in the stage of the primary reaction. In the complex process within the immune response with the various implications between B- and T-lymphocytes and the increasing knowledge of the counter-regulating humoral and cellular control mechanisms the picture of the importance of the spleen seeming to be more distinct in the intervening time becomes again more indistinct. Thus the spleen for the time being remains the enigmatical organ, as it was characterized by Sundermann already for more than ten years ago.